4.16.0 and native chevron of accordion in citation should be hidden

[compulim]

Fixes #4957.

Changelog Entry

Breaking changes

• Starting from 4.16.0, Internet Explorer is no longer supported
  • After more than a year of the Internet Explorer 11 officially retirement, we decided to stop supporting Internet Explorer. This will help us to bring new features to Web Chat
  • 4.15.9 is the last version which supports Internet Explorer in limited fashion

Fixed

• Fixes #4957. Native chevron of the accordion in citation should be hidden, by @compulim, in PR #4958

Description

Native chevron of accordion in citation should be hidden.

Specific Changes

• Bumps to 4.16.0 and bids farewell to Internet Explorer
• Hid native chevron of accordion in citation via ::-webkit-details-marker

• I have added tests and executed them locally
• I have updated CHANGELOG.md
• I have updated documentation

Review Checklist

This section is for contributors to review your work.

• Accessibility reviewed (tab order, content readability, alt text, color contrast)
• Browser and platform compatibilities reviewed
• CSS styles reviewed (minimal rules, no z-index)
• Documents reviewed (docs, samples, live demo)
• Internationalization reviewed (strings, unit formatting)
• package.json and package-lock.json reviewed
• Security reviewed (no data URIs, check for nonce leak)
• Tests reviewed (coverage, legitimacy)